Saturday, October 26, 2013

A tree of Gold

Fairy
tales for children, often speak about trees of gold with jewels and
pearls hanging from the golden branches. Obviously no sane person in
his senses is ever likely to believe in such trees. Yet, Australian
scientists have now discovered a real tree of gold. It is just an
ordinary eucalyptus tree grown in resource-rich Kalgoorlie region of
Western Australia, site of a major gold rush in the late 1800s. But
unbelievably, this tree carries gold in its trunk and even in its
leaves.

Researchers
from Commonwealth Scientific and Industrial Research Organisation
(CSIRO) located at Perth in Western Australia have literally struck
gold as they have found tiny particles of gold hidden in eucalyptus
trees. They say that the eucalyptus trees, sitting on top of gold
deposits buried deep underground, suck up the gold in their search
for moisture during droughts. According to a study published in
Nature Communications, both lab-grown and wild eucalyptus trees were
tested for traces of gold by CSIRO scientists.

Dr.
Melvyn Lintern, a geochemist at CSIRO considers finding of gold
inside tree as a 'eureka' moment. He adds:

“We
weren’t expecting this at all. The particular trees that we did the
research on appear to be bringing up gold from a remarkable 30 metres
depth, which is about the equivalent of a 10-storey building. The
eucalyptus acts as a hydraulic pump — its roots extend tens of
metres into the ground and draw up water containing the gold. As the
gold is likely to be toxic to the plant, it’s moved to the leaves
and branches where it can be released or shed to the ground.”

The
scientists at CSIRO's Perth facility used a detector known as “Maia
detector at Australian Synchrotron in Melbourne for X-ray imaging,”
to analyse extremely small particles at high resolution and found
that the gold particles with diameter one-fifth of a human hair. The
sucked up gold particles are not restricted to eucalyptus trees
though. CSIRO researchers have also found gold in the leaves of
other trees, such as the Acacia Mulga. Melvyn Lintern adds:

“We’ve
actually found gold not only in trees but in shrubs that are growing
beneath the trees as well, so (it is) not restricted to any
particular trees at all,”

The
only problem is that the quantity of gold is very small. About 500
trees growing over a gold deposit would only yield enough gold for
just a wedding ring. If that is the case, what could be the use of
this discovery? According to Melvyn Lintern, this procedure of
detection of gold in trees, known to scientists as “biogeochemical
sampling,” could turn out to be potentially extremely useful. By
sampling and analysing vegetation for traces of minerals, we might
get an idea of what’s happening below the surface, and there would
be no need to drill and damage the environment. He adds:
“It’s a more targeted way of searching for minerals that reduces
costs and impact on the environment.” This
method also could be used to detect presence of other metals in the
soil like Zinc and Copper.

A
former mining Geochemist, Nigel Radford, who has worked in mineral
exploration his entire working life, says that the implications for
gold exploration are huge. He adds:

"
A lot of this stuff has been speculated about for some time, but the
identification of the gold particles in the leaf materials is
completely convincing and very, very important for the future of
mineral exploration."

I am
slightly disappointed because I was envisaging a huge land area with
tens of thousand of trees, sucking up the hold and this can be
harvested simply by processing the fallen leaves. A sort of a green
gold mine. Gold mining is a dirty and expensive enterprise, which
damages the environment badly. This kind of green gold mining would
be great if some way if found to make the trees to suck up more gold.
New discoveries of gold have fallen worldwide by 45 per cent in the
past decade, while prices have skyrocketed as reserves steadily
dwindle. The cost of the yellow metal shot up by 482 per cent between
December 2000 and March 2013. US Geological Survey estimates that
there are 51,000 tonnes of gold left in reserves in the world.

The
real significance of this discovery is that golden eucalyptus trees
can indicate where miners might want to look. By using trees to tell
us what is in the soil, perhaps we can discover more and more of gold
reserves, without damaging the environment.